Index: b/gtk/gtkdialog.c
===================================================================
--- a/gtk/gtkdialog.c
+++ b/gtk/gtkdialog.c
@@ -700,12 +700,12 @@ update_spacings (GtkDialog *dialog)
 
   /* don't set spacing when buttons are linked */
   if (gtk_button_box_get_layout (GTK_BUTTON_BOX (priv->action_area)) != GTK_BUTTONBOX_EXPAND)
-    gtk_box_set_spacing (GTK_BOX (priv->action_area), button_spacing);
+    gtk_box_set_spacing (GTK_BOX (priv->action_area), (button_spacing == 0) ? 6 : button_spacing);
 
   if (!_gtk_container_get_border_width_set (GTK_CONTAINER (priv->action_area)))
     {
       gtk_container_set_border_width (GTK_CONTAINER (priv->action_area),
-                                      action_area_border);
+                                      (action_area_border == 0) ? 5 : action_area_border);
       _gtk_container_set_border_width_set (GTK_CONTAINER (priv->action_area), FALSE);
     }
 }
Index: b/gtk/gtkmessagedialog.c
===================================================================
--- a/gtk/gtkmessagedialog.c
+++ b/gtk/gtkmessagedialog.c
@@ -37,6 +37,7 @@
 #include "gtkintl.h"
 #include "gtkprivate.h"
 #include "gtktypebuiltins.h"
+#include "gtkcssprovider.h"
 
 /**
  * SECTION:gtkmessagedialog
@@ -327,7 +328,17 @@
 G_GNUC_BEGIN_IGNORE_DEPRECATIONS
   action_area = gtk_dialog_get_action_area (GTK_DIALOG (dialog));
 G_GNUC_END_IGNORE_DEPRECATIONS
-  gtk_button_box_set_layout (GTK_BUTTON_BOX (action_area), GTK_BUTTONBOX_EXPAND);
+  static gboolean style_added = FALSE;
+  if (!style_added)
+    {
+      style_added = TRUE;
+      GtkCssProvider *provider = gtk_css_provider_new ();
+      gtk_css_provider_load_from_data (provider,
+        "messagedialog > *, messagedialog buttonbox.dialog-action-area, messagedialog box.dialog-action-box { margin: 0; margin-top: 0; padding: 0; }",
+        -1, NULL);
+      gtk_style_context_add_provider_for_screen (gtk_widget_get_screen (GTK_WIDGET (dialog)),
+        GTK_STYLE_PROVIDER (provider), GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
+    }
 
   settings = gtk_widget_get_settings (GTK_WIDGET (dialog));
   g_object_get (settings, "gtk-keynav-use-caret", &use_caret, NULL);
@@ -374,6 +385,7 @@
     return;
 
   const char *name = gtk_window_get_title (GTK_WINDOW (dialog));
+  const gchar *icon = NULL;
   if (name && name[0])
   {
     atk_object_set_name (atk_obj, name);
@@ -415,6 +427,7 @@ setup_type (GtkMessageDialog *dialog,
 	    GtkMessageType    type)
 {
   GtkMessageDialogPrivate *priv = dialog->priv;
+  const gchar *icon = NULL;
   AtkObject *atk_obj;
 
   if (priv->message_type == type)
@@ -423,6 +436,34 @@ setup_type (GtkMessageDialog *dialog,
   priv->message_type = type;
 
 
+  switch (dialog->priv->message_type)
+  {
+  case GTK_MESSAGE_INFO:
+    icon = "dialog-info";
+    break;
+
+  case GTK_MESSAGE_QUESTION:
+    icon = "dialog-question";
+    break;
+
+  case GTK_MESSAGE_WARNING:
+    icon = "dialog-warning";
+    break;
+
+  case GTK_MESSAGE_ERROR:
+    icon = "dialog-error";
+    break;
+
+  case GTK_MESSAGE_OTHER:
+    break;
+  }
+
+  if (icon)
+    {
+      GtkWidget *image = gtk_image_new_from_icon_name (icon, GTK_ICON_SIZE_DIALOG);
+      g_object_set (image, "visible", TRUE, NULL);
+      g_object_set (dialog, "image", image, NULL);
+    }
   atk_obj = gtk_widget_get_accessible (GTK_WIDGET (dialog));
   if (GTK_IS_ACCESSIBLE (atk_obj))
     {

Index: b/gtk/ui/gtkmessagedialog.ui
===================================================================
--- a/gtk/ui/gtkmessagedialog.ui
+++ b/gtk/ui/gtkmessagedialog.ui
@@ -6,6 +6,7 @@
     <property name="resizable">0</property>
     <property name="type-hint">dialog</property>
     <property name="skip-taskbar-hint">1</property>
+    <property name="border-width">5</property>
     <child internal-child="headerbar">
       <object class="GtkHeaderBar" id="headerbar1">
         <property name="visible">1</property>
@@ -14,23 +15,25 @@
     <child internal-child="vbox">
       <object class="GtkBox" id="dialog-vbox1">
         <property name="orientation">vertical</property>
-        <property name="spacing">20</property>
-        <property name="border-width">0</property>
+        <property name="spacing">8</property>
+        <property name="border-width">2</property>
         <child>
           <object class="GtkBox" id="box">
             <property name="visible">1</property>
-            <property name="margin-start">30</property>
-            <property name="margin-end">30</property>
-            <property name="spacing">30</property>
+            <property name="margin-start">2</property>
+            <property name="margin-end">2</property>
+            <property name="spacing">12</property>
+            <property name="border-width">5</property>
             <child>
               <object class="GtkBox" id="message_area">
                 <property name="visible">1</property>
                 <property name="orientation">vertical</property>
-                <property name="spacing">10</property>
+                <property name="spacing">12</property>
                 <child>
                   <object class="GtkLabel" id="label">
                     <property name="visible">1</property>
-                    <property name="halign">center</property>
+                    <property name="halign">start</property>
+                    <property name="xalign">0</property>
                     <property name="valign">start</property>
                     <property name="wrap">1</property>
                     <property name="max-width-chars">60</property>
@@ -43,7 +46,8 @@
                   <object class="GtkLabel" id="secondary_label">
                     <property name="no-show-all">1</property>
                     <property name="margin-bottom">2</property>
-                    <property name="halign">center</property>
+                    <property name="halign">start</property>
+                    <property name="xalign">0</property>
                     <property name="valign">start</property>
                     <property name="wrap">1</property>
                     <property name="max-width-chars">60</property>
